The present invention relates to a method of wrapping products with selective functioning wrapping devices.
More specifically, the present invention relates to a method of wrapping groups of packets of cigarettes, to which the following description refers purely by way of example.
Groups of packets of cigarettes are normally wrapped by feeding each group to a cartooning machine, wrapping the group in a respective first wrapping comprising a sheet of wrapping material, e.g. semirigid cardboard, to form a respective carton of packets, and then transferring the carton to an overwrapping machine and overwrapping the carton in a respective second wrapping comprising a sheet of overwrapping material folded about the first wrapping.
In the art, wrapping machines are known, for example of the type disclosed in EP-A-529 404 or in UK-A-2 01 958, wherein the cartons of packets are overwrapped by feeding each carton, in time with a respective sheet of overwrapping material, to a feeding station of a wrapping wheel, folding the sheet into a U about the carton, joining two free end portions of the sheet to form a tubular wrapping, and, finally, closing the two ends of the tubular wrapping. The free end portions may be joined in two ways corresponding to two different formats, i.e. along a small lateral surface or a large lateral surface of the carton, and, not being retoolable to produce both formats, the wrapping machine must be changed to switch from one format to the other.
The above method involves both economic and organization drawbacks by requiring the installation of two wrapping machines, one for each format, for each production line to produce both formats and to switch rapidly from one format to the other.